For the first time, exams contained more stretching essay-style questions and candidates were expected to study fewer modules in more depth.

The new A* was also awarded to students gaining at least 90 per cent in the second year of the course – a move designed to reward exceptional performance.

But today's results will fuel claims that reforms to exams have failed to restore the A-level's credibility.

Today’s figures from the Joint Council for Qualifications show the proportion of students gaining the new top grade is the same as the number of entries awarded an A - the previous highest score - in 1965.

The results also show that girls continue to outperform boys, with 8.3% of exams awarded an A* compared with 7.9% of boys.

Figures also indicated that pupils were returning to more rigorous subjects - prompted in part by the competition to get into Britain's top universities this year.

Further maths entries increased by 11.5%, it was disclosed, while the number of pupils studying economics rose by 9% to 22,875.

Maths, technology and the three sciences - physics, biology and chemistry - were also among the fastest increases this year.

But the figures showed a continued decline in the number of pupils studying foreign languages to a high level following record falls last year.

The number of candidates taking French dropped by almost 4% to an all-time low of 13,850, while just 5,548 pupils took German, another fall of just under 4%.

But Dr Jim Sinclair, director of the JCQ, said: "This is a day for celebration. The successful introduction of the new A* grade and the increased entries for science, technology, engineering and maths subjects is good news."

Publication of today's results is expected to trigger the most desperate scramble for university places ever witnessed in Britain.

As many as 200,000 young people could be left without degree courses following a record 12 per cent rise in applications.

Students falling short of university offers by just one grade could miss out altogether, admissions tutors said, and seven students are set to compete for every spare place through clearing.

But teachers suggested that the sheer scale of the competition for places was responsible for a rise in results as students pushed harder to secure their first choice university.

Richard Cairns, the headmaster of fee-paying Brighton College, insisted the existence of the A* grade – combined with the rush for degree places – had already helped to boost A-level scores.

Some 28 per cent of A-level entries at Brighton have been awarded the new top mark, he said, compared with projections of 20 per cent.

“In the past, a very bright child could get an A without doing masses of work,” he said. “In my view, the A* has had the desired effect of encouraging students to work harder to make sure they can secure a university place.”

At the independent City of London School for Girls, some 41 per cent of A-level entries was graded A*.